1. Field of the Application
The present application relates to the stator of an axial turbomachine. The present application also relates to a turbomachine with means for pressurizing a chamber. More particularly, the present application relates to a turbomachine comprising a compressor provided with a stator with means of pressurization of a chamber.
2. Description of Related Art
A turbomachine has a rotor that can rotate relative to the stator of the turbomachine. When in operation, the rotor turns at several thousand revolutions per minute. Mechanical connections such as bearings are mounted at the interfaces between the stator and the rotor. The bearings enable the mechanical stresses to be absorbed while being designed for the speed of rotation. In order to maintain the optimum operating conditions, these bearings are supplied with lubricating oil. When in operation, this oil can turn into an oil mist.
To prevent the oil from spreading to the rest of the turbomachine, the bearings are mounted in lubrication housings that are generally sealed. The rotor shaft penetrates these housings, creating weak points in terms of sealing the junction between the fixed and moving surfaces. To avoid leaks at these joints, they have labyrinth seals. These seals can limit leakage despite the extreme conditions to which they are subjected.
To further reduce, and preferably eliminate, oil leaks, each labyrinth seal is attached to a pressurized chamber. When the turbomachine is operating, the pressure of the pressurized chamber is greater than that of the attached lubrication housing. The latter is then at a lower pressure than part of its surroundings. In this way, the labyrinth seal located in the interface eliminates all leakage except that from the pressurized chamber towards the lubrication housing; the oil can no longer run away from the latter. In these circumstances, the oil is preserved. It is not likely to spread into the remainder of the turbomachine.
To generate the pressure in the pressurized chamber, the turbomachine has a compressed air bleed system.
Patent FR 2698406 A1 discloses a device for pressurizing a chamber surrounding a bearing lubrication housing. The device comprises air bleed ducts for feeding air to the chamber. The ducts bleed air via orifices located upstream of the respective final stages of the low-pressure compressor and the high-pressure compressor. Thanks to its control system, the device provides air whose pressure and temperature are controlled regardless of the turbomachine's operating modes. However, the pressure of the bleed air is relatively low. This pressure may be too low in some configurations. In addition, the pressure losses in the ducts diminish the available pressure for pressurizing the chamber.
Although great strides have been made in the area of axial turbomachines, many shortcomings remain.